Hi,
Nice question.
It depends on what you have customized.
Looks it is the <$SPECROOT>/tomcat/webapps/spectrum/WEB-INF/console/config/custom-menu-config.xml file which stores the default values.
Have found interesting links. Take a look:
Link 1 CA Spectrum - Customizing menu's in Oneclick
Link 2 CA Spectrum - Customizing menu's in Oneclick (documentation)
Note: To customize menu's in OneClick, always copy this file in to the <$SPECROOT>/custom/console/config/ as suggested in the above link
Thanks